Hdparm: differenze tra le versioni

; -B : Set Advanced Power Management feature, if the drive supports it. A low value means aggressive power management and a high value means better performance. A value of 255 will disable apm on the drive.

; -c : Query/enable  (E)IDE 32-bit I/O support.  A numeric parameter can be used to enable/disable 32-bit I/O support: Currently supported values include 0 to disable 32-bit I/O support, 1 to enable 32-bit data transfers, and 3 to enable 32-bit data transfers with a special  sync  sequence  required  by many  chipsets.  The value 3 works with nearly all 32-bit IDE chipsets, but incurs slightly more overhead.  Note that "32-bit" refers to data transfers across a PCI or VLB bus to the interface card only; all (E)IDE drives still have only a 16-bit connection over the ribbon cable from the interface card.

; -d : Disable/enable the "using_dma" flag for this drive.  This option now works with most combinations of drives and PCI interfaces which support DMA and which are known to the kernel IDE driver.  It is also a good idea to use the appropriate -X option in combination with -d1 to ensure that the  drive itself is programmed for the correct DMA mode, although most BIOSs should do this for you at boot time.  Using DMA nearly always gives the best performance, with fast I/O throughput and low CPU usage.  But there are at least a few configurations of chipsets and drives for  which  DMA  does  not make much of a difference, or may even slow things down (on really messed up hardware!).  Your mileage may vary.

; -D : Enable/disable the on-drive defect management feature, whereby the drive firmware tries to automatically manage defective sectors by relocating them to "spare" sectors reserved by the factory for such.

; -E : Set cdrom speed.  This is NOT necessary for regular operation, as the drive will automatically switch speeds on its own.  But if you  want  to  play with it, just supply a speed number after the option, usually a number like 2 or 4.

; -g : Display the drive geometry (cylinders, heads, sectors), the size (in sectors) of the device, and the starting offset (in sectors) of the device from the beginning of the drive.

;-i : Display the identification info that was obtained from the drive at boot time, if available.  This is a feature of modern IDE drives, and may not be supported by older devices.  The data returned may or may not be current, depending on activity since booting the system.  However, the current multiple sector mode count is always shown.  For a more detailed interpretation of the identification info, refer to AT Attachment Interface for Disk Drives (ANSI ASC X3T9.2 working draft, revision 4a, April 19/93).

; -I : Request  identification  info directly from the drive, which is displayed in a new expanded format with considerably more detail than with the older -i flag.